Induced currents or Eddy currents (also known as parasitic currents or Foucault currents) are circulating electric currents induced by an alternating magnetic field in an insulated conductor. Eddy currents are not induced on an insulating material, the alternating magnetic field traversing the mentioned non-conducting material.
The use of induced currents is currently well known as a non-destructive test method for determining the thicknesses of a non-conducting coating on a conducting metal, or the thickness of a non-magnetic metal coating on a magnetic metal. However, currently there is no reliable method for the application of induced currents in the measurement of thicknesses on composite materials, such as carbon fiber, because this material, although it is a conductor, has a very low electric conductivity.
Other type of techniques, such as ultrasound techniques, have currently been proposed as non-destructive test methods for determining the thicknesses on composite materials, although this type of techniques use very complex equipment and have not provided reliable results.
The present invention is oriented to the solution of these drawbacks.